Contribution of the gasotransmitter nitric oxide to the structural and functional organization of erythrocytes under conditions of hypoxia/reoxygenation.

Hypoxia is accompanied by changes in metabolism and cell functioning. Erythrocyte hemoglobin can be involved in adaptation to hypoxia by acting as an oxygen sensor, providing a link between oxygen content and blood circulation. The mechanisms providing this function have not been completely established. The purpose of this study was to evaluate the effect of the gasotransmitter nitric oxide on the structural and functional organization of erythrocytes under conditions of hypoxia/reoxygenation. NO participated in adaptive reactions under hypoxia/reoxygenation conditions by changing hemoglobin conformation, followed by changes in hemoprotein spectral characteristics and hemoglobin affinity to oxygen together with increasing anisocytosis, volume and cell surface. The increase in intracellular NO concentrations under hypoxic conditions was provided by extracellular fluid nitrites. Molsidomine (a NO donor) induced a higher NO increase without involvement of the nitrite reductase mechanism, it caused an increase in the average erythrocyte volume, anisocytosis, and an increase in the cell surface.

Oxygen-binding properties of blood in insulin resistance with different asprosin content.

The oxygen-binding properties of blood were studied in male patients with insulin resistance (IR) with different levels of asprosin. The content of asprosin, parameters of blood oxygen transport function, as well as gas transmitters, nitrogen monoxide and hydrogen sulfide, were determined in the venous blood plasma. In the studied IR patients with increased blood asprosin content, impaired blood oxygenation was noted; IR patients with normal body weight had increased hemoglobin affinity for oxygen, while in IR patients with overweight and the 1st degree obesity, this parameter decreased. The detected increase in the concentration of nitrogen monoxide and the decrease in hydrogen sulfide may be important for the oxygen-binding properties of the blood and the development of metabolic imbalance.

[Features of ozone effect on the oxygen-dependent blood processes under hypercapnia conditions]. / Osobennosti deistviia ozona na kislorodzavisimye protsessy krovi v usloviiakh giperkapnii.

The aim of this work is to study of ozone effect on blood oxygen-dependent processes under hypercapnia conditions. The studied blood samples are pretreated with a hypercapnic gas mixture followed by the addition of ozonized isotonic sodium chloride solution (with an ozone concentration of 6 mg/l), as well as gaseous transmitters donors, nitroglycerin and sodium hydrosulfide. It has been established that hypercapnia enhanced the ozone effect on the blood oxygen transport function and was characterized by the oxyhemoglobin dissociation curve shift to the right, also increased hydrogen sulfide synthesis and absence of changes in the nitrates/nitrites concentration. Under these conditions nitroglycerin and sodium hydrosulfide did not change the parameters of the blood gas transport function, but increased the level of nitrate/nitrite and hydrogen sulfide. Preliminary hypercapnia does not eliminate the activating effect of ozone on the free radical oxidation processes, and the addition of the applied gaseous transmitter donors does not contribute to the regulation of the studied parameters.

[Prooxidant-antioxidant balance depending on endothelial nitric oxide synthase G894T polymorphism]. / Prooksidantno-antioksidantnyi balans v zavisimosti ot polimorfizma G894T gena éndotelial'noi sintazy oksida azota.

The aim of the study was to assess the prooxidant-antioxidant balance depending on endothelial nitric oxide synthase G894T polymorphism. The frequency distribution of alleles and genotypes of G894T polymorphism, nitrite concentration, hydrogen sulphide, lipid peroxidation products (diene conjugates, malonic dialdehyde), antioxidants (reduced glutathione, catalase, ceruloplasmin, retinol) were determined in venous blood of healthy males. The incidence of the GG genotype was 49.1%, GT - 44.2%, TT - 6.7%. The level of malonic dialdehyde in erythrocytes with the GG genotype is 16.8% lower than in the genotype GT. The concentration of hydrogen sulphide in the blood with the GG genotype was 27.5 [18,2; 32,5] mM, GT - 28.6 [22.9; 33.8] mM, TT - 36.3 [33.8; 42.5] mM. The content of total nitrites in plasma with the GG genotype was 10.4 [9,0; 12,5] mM, GT - 10.4 [8.9; 11.8] mM, TT - 9.4 [8.8; 9.8] mM. The genotype GG causes a lower level of malonic dialdehyde in comparison with the heterozygous genotype. The G894T polymorphism allele T is associated with a low content of total nitrites in the plasma and a high concentration of hydrogen sulfide. The data obtained suggest that if the oxygen supply of the organism is impaired, the endothelial nitric oxide synthase G894T polymorphism may be important for the oxidative stress development.

[Participation of melatonin in regulation of blood oxygen-transport function in oxidative stress induced by injection of lipopolisaccharide]. / Uchastie melatonina v reguliatsii kislorodtransportnoi funktsii krovi pri okislitel'nom stresse, vyzvannom vvedeniem lipopolisakharida.

The contribution of melatonin to the regulatoin of the blood oxygen transport function was studied during oxidative stress induced by a triple injection of lipopolysaccharide (at a dose of 5 mg/kg) in conditions of erythropoietin and gasetransmitters (nitrogen monoxide, hydrogen sulfide) action. In the experimental groups, intraperitoneal injections of melatonin (5 mg/kg), erythropoietin (1000 U/kg), hydrogen sulfide donor (NaHS 5 mg/kg), and L-arginine (100 mg/kg), were performed. The use of melatonin alone or in combination with erythropoietin, sodium hydrosulfide or L-arginine led to a decrease in lipid peroxidation products and an increase in the antioxidant protection. Melatonin, during lipopolysaccharide administration, caused changes of blood oxygen transport function: blood oxygen saturation increased, hemoglobin oxygen affinity increased. The modifying effect of melatonin on the blood oxygen transport function in combination with erythropoietin and gastransmitters did not exceed the effect of melatonin alone.

[PARTICIPATION OF GASEOUS TRANSMITTERS IN BLOOD OXYGEN TRANSPORT FUNCTION MODIFICATION UNDER THE INFLUENCE OF MAGNETIC FIELD].

Gaseous transmitters contribution in blood oxygen transport function modification under the influence of the magnetic field was studied. It is found, that irradiation of the tail artery of rats for 10 days during 10 minutes increases p50 value, indicating a decrease in the hemoglobin affinity for oxygen and is accompanied by increased concentrations of nitrate/nitrite, and hydrogen sulfide. Administration of L-arginine and nitroglycerin during magnetic field action is accompanied by a decrease of hemoglobin affinity for oxygen, which is absent when NO-synthase enzyme inhibitor (L-NAME) is added. These data suggest an important role in the formation of blood oxygen transport function such gaseous transmitters as nitrogen monoxide and hydrogen sulfide.

[THE INFLUENCE OF CARBON MONOXIDE ON THE PARAMETERS OF PROOXIDANT-ANTIOXIDANT BALANCE DURING HEPATIC ISCHEMIA-REPERFUSION SYNDROME IN RATS].

The influence of carbon monoxide on the blood and liver prooxidant-antioxidant parameters: lipid peroxidation products (conjugated dienes, malondialdehyde, Schiff bases) and antioxidant system parameters (catalase, retinol, α-tocopherol, glutathione) were investigated in rats during hepatic ischemia-reperfusion. Hepatic ischemia was induced by Pringle maneuver for 30 min, reperfusion period was 120 min. It is detected, that hepatic ischemia-reperfusion leads to intensification of lipid peroxidation with declining of antioxidant defense. Infusion of the donor CO before reperfusion period improves the prooxidant-antioxidant balance in the blood and liver. In conclusion, CO increases the antioxidant activity of the blood and liver, decreases lipid peroxidation processes, that's correct oxidative damages during hepatic ischemia-reperfusion.

[The role of NO-dependent mechanisms in melatonin antioxidant activity during hepatic ischemia-reperfusion in rats].

The antioxidant effect of melatonin on the blood oxygen transport and prooxidant-antioxidant balance during with hepatic ischemia-reperfusion (HIR) with inhibited NO synthase function has been studied in male Wistar rats. The animals were divided into 4 groups: (1) control; (2) hepatic ischemia (Pringle m., 30 min) and reperfusion for 120 min (HIR, n = 9); (9) HIR with melatonin (10 mg/kg, i.p., 10 min before HIR, n = 9); and (4) same with NO inhibitor (L-NAME, 10 mg/kg) added 5 min before melatonin administration. The indices of blood oxygen transport (p50act, pCO2, pH, pO2, etc.) and prooxidant-antioxidant balance (Schiff bases, conjugated dienes, catalase, retinol, alpha-tocopherol) were measured in blood and liver. HIR in group 1 resulted in higher p50act in mixed venous blood and sever oxidative disturbances: rise of CD and SB, decrease of alpha-T, Ret, and Cat. Melatonin in group 3 significantly improved these changes in p50act and prooxidant-antioxidant balance during HIR, but L-NAME in group 4 partly eliminated this effect. It is concluded that the antioxidant effect of melatonin during HIR is partly associated with NO-depended mechanisms, which can modify blood hemoglobin affinity to oxygen, thus limiting oxygen binding in free-radical processes.

[Erythropoietin influence on the blood oxygen transport and prooxidant-antioxidant state during hepatic ischemia-reperfusion].

The parameters of blood oxygen transport, the products of lipid peroxidation and antioxidative factors were determined in rats during the hepatic ischemia/reperfusion (HIR) under preliminary single injections of different doses ofrecombinant human erythropoietin (rhEPO). Hepatic ischemia was induced for 30 min by Pringle maneuver, reperfusion lasted 120 min. The experiments had shown that HIR led to the significant decreases in the hemoglobin oxygen affinity, activation of lipid peroxidation, depletion of the antioxidant system, increases blood transaminases (ALT and AST). rhEPO in dose 100 IU/kg aggravates decreasing hemoglobin oxygen affinity, improves some antioxidant parameters, but didn't correct lipid peroxidation or plasma transaminases during HIR. rhEPO infusion id dose 1000 IU/kg leads to oxyhemoglobin dissociative curve shift left-wards, improves prooxidant-antioxidant balance and plasma ALT, AST activities at the end of re-perfusion period.

[Nitric oxide modification of hemoglobin oxygen affinity in different conditions of oxygenation].

The aim of the present study was to investigate the role of nitric oxide (NO) in the regulation of hemoglobin oxygen affinity (HOA) in the presence of different oxygen partial pressure. In this research the effect of NO donors on gas-transport, acid-base balance, HOA indexes, metHb, iron-nitrosylhemoglobin amounts, and total nitrite/nitrate concentration was estimated in vitro. Experimentally, positive correlation was found between NO-dependent shift of HOA and hemoglobin oxygen saturation level. In conclusion, NO is a component of autonomous intraerythrocytic system of HOA regulation, which action is determined by oxygen in the blood. We assume that the physiological significance of such NO action is to maintain aerobic metabolism through optimal blood oxygenation in the pulmonary circulation, on the one hand, and, on the other hand, its compensation under low oxygen tension in the working tissues.

[Effects of melatonin on oxygen-dependent processes].

Original and literature data on melatonin effects on various oxygen-dependent processes, in particular, blood oxygen transport and the free-radical reactions, are analyzed. Melatonin influences the oxygen binding properties of hemoglobin by changing hemoglobin oxygen affinity and optimizes the process of tissue oxygenation and prooxidant--antioxidant balance by reducing oxygen participation in free-radical processes.

[Oxygen-binding capacities of hemoglobin and nitric oxide].

The analysis of the literature and our own results indicates that a nitric oxide carries out a role the allosteric effector of hemoglobin, changing its affinity to oxygen and defining a condition of oxygen transport blood function. It is important point for modification of functional properties of hemoglobin and its participation in the flow of oxygen in tissues, which plays an important role in development of disadaption reactions at stress and decreased bioactivity of the nitric oxide at the endothelial dysfunction. These findings give possiblity to creat the new ways to correct hypoxical conditions through influence on oxygen-binding properties of the blood and activity of L-arginin-NO system.

[Sauna effect on blood oxygen transport function and proxidant/antioxidant balance in youths].

There was investigated sauna effect on blood oxygen transport function and proxidant/antioxidant balance in 18 to 22 years old males. Subjects being tested underwent thermal exposure once per week over a period of 5 months (20 procedures). There were two exposure over the course of sauna bathing (temperature 85-90 degrees C, humidity 10-15%): the first exposure lasted for 5 minutes and the second one for 10 minutes. Dry air sauna in youth's leads to respiratory alkalosis, increases pO2, decreases haemoglobin binding capacity to venous blood oxygen thus facilitating oxygen transport into body tissues. Single sauna visit results in oxidative stress (augmentation of free radical processes and deterioration of antioxidant defence mechanisms), while its manifestations being diminished after multiple thermal exposures. Increase in nitrogen monoxide formation being observed might matter for the modification of the oxygen dependent processes of the human body.

[Effect of sodium nitroprusside on hemoglobin oxygen binding properties of the blood during hepatic ischemia-reperfusion in rabbits].

The parameters of blood oxygen transport were determined in rabbits during the hepatic ischemia/reperfusion (HIR) with or without sodium nitroprusside (SNP) administration. Hepatic ischemia was induced for 30 min by a. hepatica propria clamping, reperfusion lasted 120 min. Indices of blood oxygen transport (hemoglobin-oxygen affinity index (p50), pO2, pH, pCO2, HCO3-, TCO2, ABE, etc.) and nitrite/nitrate (NO(x)) amounts were measured in blood during HIR. Animals were subdivided into two groups: 1st group--HIR; 2nd--HIR plus SNP infusion (SNP, Sigma, i.v. 10 mcmol/kg). The experiments had shown that HIR led to significant acidic changes in the acid-base balance and high blood p50. The SNP infusion in the 2nd group led to less changing in the p50 values during HIR which were accompanied with high NO(x) levels. We conclude that oxyhemoglobin dissociation curve shift leftwards after SNP administration promotes the maintenance liver during ischemia-reperfusion.

[Erythropoietin and blood oxygen transport: new sides of well-known problem].

Original results and literature data on the erythropoietin effects and mechanisms of action are analyzed. The action of this substance on blood oxygen transport is not only manifested by direct change in hemoglobin concentration and, correspondingly, by increased oxygen capacity, but is also mediated by modulators of hemoglobinaffinity to oxygen, in particular, via nitric oxide effect on hemoglobin.

[Peroxynitrite effect on the haemoglobin oxygen affinity in vitro in presence of different partial pressure of carbon dioxide].

Peroxynitrite (ONOO-) besides its toxic possesses regulatory action that includes the modulation of oxygen binding properties of blood. The aim of this work was to estimate ONOO- effect on the haemoglobin oxygen affinity (HOA) in vitro in presence of different partial pressure of carbon dioxide (CO2). The ONOO- presence in venous blood in conditions of hypercapnia induced oxyhaemoglobin dissociation curve shift leftward while in hypocapnic conditions the result of a different character was obtained. The revealed effect of ONOO- is realized, possibly, through various modifications ofhaemoglobin whose formation is dependent on the CO2 pressure. The ONOO- influences the HOA in different manner that can be important in regulation of blood oxygenation in lungs and maintenance of oxygen consumption in tissues.

[Effect of erythropoietin on blood oxygen transport in rats during cold exposure and subsequent rewarming].

Effect of erythropoietin (EPO) preparation (epocrine) on the blood oxygen transport in rats exposed to cold (120 min in a water-cooled box at 19 degrees C) and then rewarmed (next 120 min at a mean heating rate of 0.06 degrees C/min) has been studied. The administration of EPO reduced the body temperature fall at the end of cold exposure and enhanced its rise during the rewarming stage. The effect of EPO in tested rats is associated with a decrease in the hemoglobin affinity to oxygen, which increases the oxygen supply of tissues and improves the organism adaptability to cold.

[Effect of melatonin on the blood oxygen-carrying function and prooxidant-antioxidant balance after lipopolysaccharide injection].

Effects of melatonin on the blood oxygen-carrying function and prooxidant - antioxidant balance in the organism were studied 12 h after lipopolysaccharide injection in rabbits. The treatment with melatonin (intraperitoneally in a dose of 4 mg/kg) before endotoxic lipopolysaccharide injection (intravenously 500 microg/kg) improved oxygen transport function of the blood, increased the hemoglobin-oxygen affinity, decreased nitrates/nitrites level, reduced the gain of free-radical processes, and increased the level of antioxidant protection factors in test animals. It is concluded that melatonin modulates the blood oxygen-carrying function and prooxidant - antioxidant balance through NO-dependent mechanisms, thus reducing the negative action of endotoxin on the organism.

[Effect of 1-methylnicotinamide on prooxidant-antioxidant balance parameters in rats during hepatic ischemia-reperfusion].

We have studied the effect of 1-methylnicotinamide (MNA) on prooxidant - antioxidant balance parameters by measuring the concentrations of lipid peroxidation products (conjugated dienes (CD) and Schiff bases (SB)) and antioxidant system factors (alpha-tocoferol (alpha-T), retinol (Ret) in the blood and liver homogenates and by evaluating the activity of catalase (Cat) and alanine and aspartate aminotransferases in the blood plasma in the course of hepatic ischemia-reperfusion in a group of 16 adult male Wistar rats (weighing 360-440 g). The anmals were divided into two groups: (1) hepatic ischemia (30 min, m. Pringle) and reperfusion (120 min) (HIR, n = 8); (2) HIR with MNA (100 mg/kg. i.p. 10 min before HIR, n = 8). In the first group, the plasma level of CD raised to 264.4% (p < 0.05), SB to 633.3% (p < 0.05), the concentration of alpha-T decreased by 19% (p < 0.05), that of Ret by 35.8 % (p < 0.05), and Cat by 45.8 % (p < 0.05) at the end of reperfusion as compared to control values before ischemia. In the second group, at the end of reperfusion the level of CD increased only to 51.4% (p < 0.05), SB to 130.3% (p < 0.05), Cat to 65% (p < 0.05), and the concentration of alpha-T in the plasma decreased only to 11% (p < 0.05), and Ret to 20.7% (p < 0.05). It is concluded that MNA significantly improves the prooxidant - antioxidant balance parameters during hepatic ischemia-reperfusion in rats.

[Role of NO in the coronary vessel responses to agonists of various adrenoceptor subtypes].

We have studied the role of NO in coronary flow responses to agonists of alfa-2, beta-1, beta-2 and beta-3 adrenoceptors in the isolated mouse heart perfused according to the Langendorff method. The selective alfa-2 adrenoceptor agonist clonidine (10(-8) - 10(-6) M) displayed coronary vasoconstrictor properties as it induced dose-dependent decrease in the coronary flow. On the contrary, the nonselective beta-1/beta2/beta-3 adrenoceptor agonist isoprenaline (10(-8) - 10(-7) M) was a coronary vasodilator and caused dose-dependent increase in the coronary flow. The response to clonidine or isoprenaline was not changed by the presence of the NO-synthase inhibitor L-NO-nitroarginine methyl ester (L-NAME, 5 x 10(-4) M). The selective beta-3 adrenoceptor agonist BRL 37344 at high concentrations (10(-6) - 10(-5) M) produced a coronary vasodilator effect, but this effect was completely blocked by the beta-1/beta-2 adrenoceptor antagonist nadolol (10(-5) M). It is concluded that NO does not play any significant role in the coronary vascular responces mediated by alfa-2, beta-1, and beta-2 adrenoceptors in the isolated mouse heart. The functionally active beta-3 adrenoceptors seem to be not active in the coronary circulation in the isolated mouse heart.